[1] Born in Zlonice, near Kladno, in Bohemia in the Holy Roman Empire, Krumpholz was the son of a bandmaster in a French regiment who lived in Paris during childhood, learning music from his father.
He said that Krumpholz's name was "immortalized by his intimacy with Beethoven, who was exceedingly fond of the older man, and who used to jokingly call him mein Narr (my fool).
[1][2] Bone wrote that Krumpholz frequently played the mandolin to Beethoven and indicated that it influenced the composer to write music for the instrument.
He mentioned research done by Dominco Artaria, who had bought a Skizzenbook, containing sketches of some of Beethoven's music.
Artaria stated in his Aittographische Skizze that Beethoven intended to write a sonata for mandolin and piano for Krumpholz.